Optical resolution of the racemic modification of 2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide

Abstract

D-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide and 1-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide are produced by reacting d1-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide with optically active camphor-10-sulfonic acid or optically active 3-bromo-camphor-10-sulfonic acid as a resolving agent in a lower alkyl ester of acetic acid containing a lower alkyl carboxylic acid, thereby forming diastereomeric salts, and optically resolving said diastereomeric salts.

What is claimed as new and is intended to be secured by Letters Patent is: 
     
       1. A process for the optical resolution of dl-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide which comprises reacting dl-2,2'-bis(diphenylphosphino)-1,1'-binaphthyldioxide with any one of the optically active resolving agents d-camphor-10-sulfonic acid, l-camphor-10-sulfonic acid, d-3-bromocamphor-10-sulfonic acid or l-3-bromocamphor-10-sulfonic acid in a lower alkyl ester of acetic acid containing a lower alkyl carboxylic acid, thereby forming diastereomeric salts; and resolving said diastereomeric salts to afford the optically active isomers, and wherein said resolving agents are used in the amount of about 1 to 5 moles per mole of dl-DINAPO, and said lower alkyl ester of acetic acid is used in the amount of about 2 to 5 times by weight of the amount of dl-DINAPO, and wherein said lower alkyl carboxylic acid is used in an amount of about 1 to 20 times by mole per mole of dl-DINAPO. 
     
     
       2. The process as claimed in claim 1, wherein said lower alkyl ester of acetic acid is methyl acetate, ethyl acetate and propyl acetate and said lower alkyl carboxylic acid is acetic acid, propionic acid and butyric acid. 
     
     
       3. The process as claimed in claim 1, wherein said resolving agents are used in the amount of about 1 to 2 moles per mole of dl-BINAPO. 
     
     
       4. The process as in claim 1, wherein said lower alkyl carboxylic acid is added dropwise to the solution of lower alkyl ester of acetic acid.